My Baby's Got a Secret
by JediFighterPilot2727
Summary: Kara lets it slip that she's Supergirl but doesn't notice. Lena decides to see where it goes.


**Prompt: Imagine Lena knowing that Kara is Supergirl but not really saying anything about it. Instead she just talks to Kara and Supergirl as the same person (i.e. mentioning things to Kara that she's talked to Supergirl about) and Kara's too distracted by her huge crush on Lena to notice. Then one day Kara suddenly realises that Lena has known the whole time and she's basically confirmed it accidentally and she sort of panics a little. Lena calms her down and assures her that it's ok.**

Lena Luthor was no idiot.

She had graduated Summa Cum Laude from Harvard with a double major in business and computer engineering.

She was the CEO of a multi-billion dollar corporation before the age of 35.

She had literally hundreds of patents filed under name.

She had read a ridiculous amount of books, fiction and non-fiction, hell, she had even read the dictionary once.

It was not hard to figure out that Kara Danvers was Supergirl.

Glasses and a ponytail did not a good disguise make. Especially when you were trying to hide from the girl who had actually designed facial recognition software.

She didn't say anything though.

It was cute, watching Kara try and cover her tracks, try and pretend to be two different people. The excuses she came up with when cutting out of dates early, or leaving Lena's bed in the middle of the night were overused at best and completely unbelievable at worst.

Really, how many times could her sister get locked out of her apartment? Lena had spent enough time around Alex Danvers to know that she was of above average intelligence, and definitely not the type to lose her keys three times in one week. Besides, she highly suspected that Alex would take it as a challenge to break into her own apartment rather than call her sister for help.

But Lena never complained, never said a word.

When Kara would leave in a rush with a mumble excuse, she would simply turn on the news and bite her lip with worry as she watched Supergirl fly into a burning building or stop a robbery, or worse - fight some alien threat high above National City.

She wondered how long they would be able to keep it up.

Who would slip first.

If she would go to undress Kara and find the Super suit underneath.

Or if Supergirl would accidentally kiss her before flying off her balcony.

It was like a low stakes game of poker face that kept her heart racing every time they parted ways. Whenever the inevitable happened, she thought perhaps they would laugh about it, Kara's eyes scrunching up at the corners as she giggled about failing at keeping her secret identity a secret.

Nevertheless, she always thought it would be a breathless moment of revelation and confession.

Never in a million years did she think it would happen like this.

She was sitting at her desk when Supergirl touched down on her balcony, cape billowing behind her in the night air.

"Supergirl, to what do I owe the pleasure?"

"Just thought I'd check in on you, see if you were feeling any better."

Lena froze on her way to the bar.

She had sniffled twice this morning over breakfast and Kara had freaked out, mumbling about colds and how the human race was so fragile. She half expected her day to be filled with texts and calls from her overprotective girlfriend, but alas, a rogue alien had attacked the city and instead her day was filled with watching news reports of Supergirl.

She could play this one of two ways - confront Kara about the slip, or let it slide to see how it played out.

"Much better, I told you it was just allergies."

"Well Ms. Luthor, one can never be too sure."

She bit back a laugh at the 'Ms. Luthor' the idea of any formality between them - particularly after where Kara's mouth had been last night.

"I appreciate your concern. Especially after how busy you've been today."

She reached for her favorite bottle of vodka, only to find it was empty.

"I'd offer you a drink, but it seems I'm all out."

"It's fine, probably best that I don't drink and fly anyway." Kara smirked, and Lena was two seconds away from leaning forward and brushing the stray curl out the hero's eyes when the sound of a siren filtered through the open balcony door.

"I suppose you're needed."

"A hero's work is never done." Kara said ruefully. "Have a good night Ms. Luthor."

And then she was gone, a blue and red streak across the sky as Lena sat back at her desk to consider this new development.

There was a bottle of her favorite vodka sitting on the kitchen counter when she went to fix breakfast the next morning.

"What's this?"

"Oh, it's for your office, I picked it up on my way home last night." Kara rounded the corner, glasses fogged as she towel dried her hair. "Just a heads up, I'm pretty sure Snapper wants me to get the story on L-Corp's newest stock offering today. You want me to bring food by your office for lunch or do you wanna eat out?"

Lena's eyes traced down Kara's still naked form.

"Uhhh, out. I'll make reservations at that fancy burger place you like."

"Sounds great!"

"You know, I could always go in a little late today . . . " She stepped forward to trail a lazy hand up Kara's abs and her girlfriend smiled devilishly.

"I could always tell Snapper I got caught chasing down a story . . ."

Just as their lips were about to meet, the tv squawked from the living room.

"This just in, the foundry plant on the westside of the industrial district has went up in flames this morning, reports suggest -"

Kara's face fell.

"On second thought, he might not like it if I'm late again; I better go."

"Up, up, and away?"

"Yep, I mean my office is on the top floor!" Her nose scrunched in that adorable way that Lena loved and then she was gone, returning in entirely too short a time to have completely dressed, done her hair AND put on makeup.

"I'll see you for lunch!" Kara promised and with a quick peck on the lips she was out the door.

Lena didn't even have to turn around to know that Supergirl was speeding past her window.

When Kara showed up for the interview at the restaurant, she still smelled slightly like smoke.

"Hey, thanks for ordering for me!" she said grinning as she saw the two gigantic burgers and the plate full of fries Lena had ordered for her.

"I figured all the fire fighting might whet your appetite." Lena said carefully, taking a long draw from her glass of merlot.

Kara nodded furiously, stuffing french fries in her face at a rate that would be unbecoming for anyone else.

"And Snapper was a total . . . jerk face. I can't wait until Ms Grant comes back and puts him in his place."

"I could always call and take him down a few notches if you like."

Kara smiles at her, and she thinks this might be the closest anyone's ever gotten to the sun without being incinerated.

"I can handle him, maybe this article will get him off my back."

"Well I will gladly answer all the questions you throw at me. I can even arrange a private tour if that helps."

"A private tour of what?"

"My bedroom."She says simply, and winks in a way that makes Kara drop her burger back to her plate, coughing.

"I'll have to take you up on that. Off the record, of course."

They continue in much the same way for the next few weeks, Kara and Supergirl blending together until she almost forgets she's not supposed to know they're the same person.

It all comes to a head at game night, Lena's feet in Kara's lap - nimble fingers working their magic and massaging away the tightness left from hours spent in high heels.

"There you go, 450 measly bucks for landing on your stupid Baltic Avenue hotel." Winn passed a few bills to Kara from his ever growing stack.

"I'm telling you," Kara grinned gleefully; "This is how the game is won, small victories. Eventually I will crush you like I crushed that missile that was headed for city hall this morning!"

The room stopped.

Everyone turned to Kara who was holding out the dice for Lena to blow on like their playing craps in Vegas and not just Monopoly in Kara's living room.

"Ahem." Alex cleared her throat, looking pointedly at Kara.

"What? I totally crushed it. Literally."

"Kara." Alex looked at Lena now. "She means she totally crushed the story Snapper sent her to write about SUPERGIRL taking care of the missile."

It's then Kara froze, eyes wide with fear and unease.

"I yes, I - that's - Snapper and the story-"

"Kara." Lena interrupts softly, sitting up and resting a hand on her girlfriend's shoulder. "This morning you told me you were going to take a flight around the neighborhood to check for trouble. And last night Supergirl showed up on my balcony bitching about how Snapper Carr is 'a rude little man'."

"She did? I - well-"

"Kara." she repeats again. "It's okay."

Kara's shoulders sag in what she hopes is relief.

"You're not mad?"

"I've known you were Supergirl from the very beginning. I just wanted to be comfortable enough to tell me yourself. And then you started letting things slip - Supergirl knew things only you should have known, you suddenly had a penchant for saving the world. I just assumed your subconscious was okay with me knowing and you just hadn't quite figured it out yet.

"Oh."

Kara's eyes locked on hers and the rest of the room melted away.

"I should have said something after you slipped the first time but I didn't really know what to say."

"I should have told you I was Supergirl from the very beginning."

She leaned forward, adjusting Kara's crooked glasses.

"You had your reasons, there are a lot of people at risk if the wrong people find out your identity."

"Yeah, but you're one of those people at risk now, you should have known what you were getting into."

"My girlfriend is pretty awesome, I'm sure she could protect me."

A blushing Kara giggled and Lena continued.

"Not that I'm a distressing damsel or anything."

"No, no definitely not." Kara's bright blue eyes were inches away now. "You can certainly take care of yourself."

"Guys." Alex's voice was deadpan but it still startled them apart. "We're all still here. So before this gets too-" She waved a hand, "mushy; I just want to stop you."

"Yeah can we get back to the part where I'm kicking everybody's ass at Monopoly?" Winn whined.

And just like that, her world settles back to normal.

A Luthor and a Super.

Who would have thought.

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